Neuroprotective Effects of Desert Milk Exosomes in LPS-Induced Cognitive Decline: Role of Microglial M2 Polarization and AMPK Signaling

Background/Objectives: Hippocampal neuroinflammation (HNF) is a key pathological feature in neurodegenerative disorders. Milk-derived exosomes, as bioactive extracellular vesicles, have underexplored potential in regulating brain neuroinflammatory responses. This study aimed to characterize desert milk exosomes (D-Exo) and investigate their neuroprotective and anti-neuroinflammatory effects in LPS-induced HNF mice model and an LPS-stimulated BV2 microglia. Methods: Exosomes were isolated from desert and non-desert milk (ND-Exo) for proteomic analysis. After pretreating BV2 cells with exosomes and stimulating with LPS, their inflammatory responses and polarization were assessed by RT-PCR. Balb/c mice were orally gavaged with D-Exo or 0.9% NaCl for 28 days before LPS injection. Cognitive function was assessed via behavioral tests, with microglial/astrocyte activation analyzed by immunofluorescence. Results: D-Exo exhibited superior stability and a unique proteomic profile enriched with proteins linked to neuroinflammation and blood-brain barrier (BBB) integrity, notably within the AMPK signaling pathway. In vitro, D-Exo shifted LPS-stimulated microglia from the M1 to the M2 phenotype. In vivo, it alleviated HNF and cognitive decline, reduced Aβ1-42 and Tau deposition, elevated BDNF and MAP2, and suppressed neuroinflammation and glial activation. Conclusions: D-Exo is enriched with specific proteins, attenuates neuroinflammation and cognitive decline by regulating microglial M1/M2 polarization and AMPK pathway, highlighting its preventive potential.